1. Field of the Invention
The present invention relates to laser rangefinders (LRFs), more specifically to fiber optically coupled LRFs.
2. Brief Description of Related Art
Currently, a laser rangefinder (LRF) combined with a camera, of any waveband, mounted on a gimbal assembly is used to view and measure a range to objects within a system field of regard. However, the weight and size of the LRF dramatically increases the size of the gimbal assembly. This is due to the scaling that occurs as the structure, motors, drive power, drive electronics and support requirements of the gimbal assembly increase to accommodate the LRF. This increased size of the gimbal assembly increases a swept volume in a sensor package and thereby increasing the overall size and weight of the gimbal assembly.
Further, having the LRF in the gimbal assembly couples the waste heat (typically, lasers are at best 30% efficient) into the structure that combines a camera optical bench in the gimbal assembly. This heat load may cause boresignt and optical distortions that can degrade the overall system performance. Further, if mirrors are used to couple the LRF onto the gimbal assembly then the heat problem can be averted but the gimbal assembly complexity and size may increase. Generally, the gimbal assemblies have two to three axes of motions and each axis of motion requires a set of mirrors with their accompanied alignment, limited field, of view and transmission losses.